1. Field of the Invention
The present invention relates to a communication apparatus having a plurality type of network interfaces.
2. Related Background Art
Network technology called UPnP (Universal Plug and Play) has been proposed (Reference Document: Universal Plug and Play Device Architecture, Version 1.0, 08 Jun. 2000). UPnP can configure a network having one or more types of communication media (such as IEEE1394, USB and Bluetooth) by using the IP (Internet Protocol). UPnP prescribes a “device” (hereinafter called a UPnP device) providing one or more services and a “control point” which remotely controls a UPnP device having a predetermined service. A network in conformity with UPnP is hereinafter called a “UPnP network”.
With a present UPnP network, however, if a UPnP device has a plurality type of network interfaces, this UPnP device acquires a plurality of IP addresses. It appears therefore as if a plurality of UPnP devices exist on the UPnP network.
FIG. 5 is a diagram illustrating a disadvantage of the present UPnP network. As shown in FIG. 5, if a DVCR (Digital Video Cassette Recorder) as an example of a UPnP device having three kinds of network interfaces (for example, an IEEE1394interface, a USB interface and a Bluetooth interface) participates in an UPnP network, this DVCR acquires three IP addresses in accordance with the procedure prescribed in UPnP. The IEEE1394 interface is a network interface in conformity with IEEE1394-1995 (Reference Document: IEEE Std 1394-1995, IEEE Standard for a High Performance Serial Bus, Institute of Electrical and Electronics Engineers, Inc.), the USB interface is a network interface in conformity with USB (Reference Document: Universal Serial Bus Specification Revision 2.0, Apr. 27, 2000), and the Bluetooth interface is a network interface in conformity with Bluetooth (Reference Document: Specification of the Bluetooth System, version 1.1, Feb. 22, 2001).
In such a case, a DTV (Digital Television Receiver) as an example of a control point assumes that three DVCRs exist on the UPnP network, and displays three DVCR control panels on its screen. FIG. 6 shows an example of a DTV screen. As shown in FIG. 6, three DVCR control panels are displayed on the DTV screen.
A user therefore believes that there are three DVCRs, and operates on each control panel. However, in this case, since only one DVCR exists actually, DVCR cannot operate in the manner intended by the user.